Lighting assembly with adjustable light output

ABSTRACT

A lighting assembly includes a light guide and light source. The light guide includes light input regions, at least one of the light input regions associated with an optical modifying characteristic, and the light guide is configured to propagate light by total internal reflection. The light source is located adjacent the light input regions. The light source and light input regions are variably positionable relative to one another to vary a location at which light is incident on the light input regions such that light emitted from the light source is selectively apportioned between the light input regions. A characteristic of the light output from the lighting assembly is modified based on the optical modifying characteristic of the at least one of the light input regions and the relative positioning of the light source and the light input regions.

RELATED APPLICATION DATA

This application claims the benefit of U.S. Provisional PatentApplication No. 61/453,763, filed Mar. 17, 2011, and claims the benefitof U.S. Provisional Patent Application No. 61/454,218, filed Mar. 18,2011, the disclosures of which are incorporated herein by reference intheir entireties.

BACKGROUND

Energy efficiency has become an area of interest for energy consumingdevices. One class of energy consuming devices is lighting devices.Light emitting diodes (LEDs) show promise as energy efficient lightsources for lighting devices. But control over color and light outputdistribution is an issue for lighting devices that use LEDs or similarlight sources.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a light bulb representing an exemplarylighting assembly with adjustable light output, where a portion of ahousing of the light bulb is cut away to show a light source assembly;

FIG. 2 is a schematic view of a lighting fixture representing anotherexemplary lighting assembly with adjustable light output;

FIGS. 3-6 are schematic views showing part of an embodiment of alighting assembly having adjustable light output;

FIGS. 7-10 are schematic views showing part of another embodiment of alighting assembly having adjustable light output;

FIGS. 11-13 are schematic views showing an arrangement of light inputregions of a lighting assembly having adjustable light output;

FIGS. 14-16 are schematic views showing part of another embodiment of alighting assembly having adjustable light output;

FIG. 17 is a schematic view showing another arrangement of light inputregions of a lighting assembly having adjustable light output;

FIGS. 18 and 19 are schematic views showing another arrangement of lightinput regions of a lighting assembly having adjustable light output; and

FIGS. 20 and 21 are schematic views showing part of another embodimentof a lighting assembly having adjustable light output.

DESCRIPTION

Embodiments will now be described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. The figures are not necessarily to scale. Features that aredescribed and/or illustrated with respect to one embodiment may be usedin the same way or in a similar way in one or more other embodimentsand/or in combination with or instead of the features of the otherembodiments.

Aspects of this disclosure relate to a lighting assembly. As illustratedin FIG. 1, one type of lighting assembly 100 is a light bulb 200. Asillustrated in FIG. 2, another type of lighting assembly 100 is alighting fixture 300. The lighting assembly 100, whether a light bulb200 (e.g., as shown in FIG. 1), a lighting fixture 300 (e.g., as shownin FIG. 2), or another type of lighting device, is described in greaterdetail herein with reference to the various embodiments illustrated inthe figures.

The lighting assembly includes a light guide and a light source. Thelight guide includes light input regions, at least one of the lightinput regions associated with an optical modifying characteristic, andthe light guide is configured to propagate light by total internalreflection. The light source is located adjacent the light input regionsand the light source and light input regions are variably positionablerelative to one another to vary the location at which light is incidenton the light input regions. Light emitted from the light source isselectively apportioned between the light input regions so that acharacteristic of the light output from the lighting assembly ismodified based on the optical modifying characteristic of the at leastone of the light input regions and the relative positioning of the lightsource and the light input regions.

In the case of the light bulb, the light bulb additionally includes abase configured to mechanically mount the light bulb and receiveelectrical power.

With additional reference to FIGS. 3-6, the lighting assembly 100includes a light guide 102, which is a solid article made from, forexample, acrylic, polycarbonate, glass, or other appropriate material.The light guide 102 may be rigid or flexible. The light guide 102 mayalso be a multi-layer light guide having two or more layers. The lightguide 102 includes a first major surface 106 and a second major surface108 opposite the first major surface 106. The light guide 102 isconfigured to propagate light by total internal reflection (TIR) betweenthe first major surface 106 and the second major surface 108.

The light guide 102 includes light extracting elements (not shown) in oron at least one of the major surfaces 106, 108. Light extractingelements that are in or on a major surface 106, 108 will be referred toas being “at” the major surface. Each light extracting element functionsto disrupt the total internal reflection of the propagating light thatis incident on the light extracting element. In one embodiment, thelight extracting elements reflect light toward the opposing majorsurface so that the light exits the light guide 102 through the opposingmajor surface. Alternatively, the light extracting elements transmitlight through the light extracting elements and out of the major surfaceof the light guide 102 having the light extracting elements. In anotherembodiment, both of these types of light extracting elements arepresent. In yet another embodiment, the light extracting elementsreflect some of the light and refract the remainder of the lightincident thereon. Therefore, the light extracting elements areconfigured to extract light from one or both of the major surfaces 106,108.

Light guides having such light extracting elements are typically formedby a process such as stamping, molding, embossing, extruding, laseretching, chemical etching, or another suitable process. Light extractingelements may also be produced by depositing elements of curable materialon the light guide 102 and curing the deposited material using heat,UV-light or other radiation. The curable material can be deposited by aprocess such as printing, ink jet printing, screen printing, or anothersuitable process.

Exemplary light extracting elements include light-scattering elements,which are typically features of indistinct shape or surface texture,such as printed features, ink-jet printed features,selectively-deposited features, chemically etched features, laser etchedfeatures, and so forth. Other exemplary light extracting elementsinclude features of well-defined shape, such as V-grooves, lenticulargrooves, and features of well-defined shape that are small relative tothe linear dimensions of the major surfaces 106, 108, which aresometimes referred to as micro-optical elements. The smaller of thelength and width of a micro-optical element is less than one-tenth ofthe longer of the length and width of the light guide 102 and the largerof the length and width of the micro-optical element is less thanone-half of the smaller of the length and width of the light guide. Thelength and width of the micro-optical element is measured in a planeparallel to the major surface 106, 108 of the light guide 102 for flatlight guides or along a surface contour for non-flat light guides 102.

Micro-optical elements are shaped to predictably reflect or refractlight. However, one or more of the surfaces of the micro-opticalelements may be modified, such as roughened, to produce a secondaryeffect on light output. Exemplary micro-optical elements are describedin U.S. Pat. No. 6,752,505 and, for the sake of brevity, are notdescribed in detail in this disclosure. The micro-optical elements mayvary in one or more of size, shape, depth or height, density,orientation, slope angle or index of refraction such that a desiredlight output from the light guide is achieved.

The light guide 102 has at least one external edge, the total number ofexternal edges depending on the configuration of the light guide 102. Anexternal edge is an edge that is not completely surrounded by the lightguide 102. In the case where the light guide 102 is rectangular (e.g.,as shown in FIG. 4), the light guide 102 has four external edges 110,112, 114, 116 (e.g., side edges 110, 112, end edge 116, and light inputedge 114). In other embodiments, the light guide has a different shape,and the total number of external edges is different. For example, wherethe light guide 102 is a hollow cylinder (e.g., as shown in FIG. 1), isfrustroconical, is a frustrated pyramid, is a dome with a hole cut atthe dome's apex, or another similar shape, the light guide has twoopposing external edges 114, 116. In an embodiment where the light guide102 is shaped like a dome or has a shape approximating the bulbous shapeof a conventional incandescent bulb, the light guide 102 has a singleexternal edge. Other geometries for the light guide 102 result in acorresponding number of external edges. Depending on the geometry of thelight guide 102, each external edge may follow a straight path or acurved path, and adjacent edges may meet at a vertex or join in a curve.

In some embodiments, the light guide 102 includes an internal edge (notshown), which is an edge completely surrounded by the light guide 102.The internal edge is usually the edge of a hole that extends between themajor surfaces of the light guide 102.

The length and width dimensions of each of the major surfaces 106, 108are much greater, typically ten or more times greater, than thethickness of the light guide 102. The thickness is the dimension of thelight guide 102 in a direction orthogonal to the major surfaces 106,108. In the rectangular embodiment, the length (measured from externaledge 114 to external edge 116) and the width (measured from externaledge 110 to external edge 112) of each of the major surfaces are bothmuch greater than the thickness of the light guide 102. The thickness ofthe light guide 102 may be, for example, about 0.1 millimeters (mm) toabout 10 mm.

At least one of the edges, whether an external edge or internal edge,serves as a light input edge. Light emitted from one or more lightsources 104 is directed toward the light input edge. In the embodimentshown in FIGS. 3-6, external edge 114 serves as the light input edge.

The light input edge 114 includes light input regions. The light inputregions are associated with different optical modifying characteristics.An optical modifying characteristic is indicated by an effect that thelight input region has on light that is incident thereon. For purposesof this description, a light input region that lacks an opticalmodifying characteristic will be considered specularly transmissive,even though specularly transmissive material refracts light that passesthrough the material at a non-zero angle of incidence. Exemplary opticalmodifying characteristics and the effect that the light input regionshave on light incident thereon are discussed in more detail below withreference to the illustrated embodiments.

The light input edge includes any appropriate number of light inputregions. Furthermore, any appropriate number of light input regions maybe associated with a given light source. In the illustrated embodiments,the change in optical modifying characteristic from one light inputregion to another light input region is abrupt. In other embodiments,the transition between the light input regions may be gradual.

FIGS. 3-6 illustrate an embodiment where light source 104 is associatedwith input regions 117, 118. In the illustrated embodiment, the opticalmodifying characteristic of one of the light input regions modifies thelight ray angle distribution of the light incident thereon. In anexample, light input region 117 includes optical elements, an exemplaryone of which is shown at 119. The reference numeral 119 willadditionally be used to refer to the optical elements collectively. Theoptical elements 119 modify the light ray angle distribution of thelight incident thereon. In this disclosure, the term light ray angledistribution is used to describe the variation of the intensity of lightwith ray angle (typically a solid angle) over a defined range of rayangles. In an example in which the light is input to an edge-lit lightguide, the defined range of ray angles is from −90° to +90° relative tothe normal to the light input region 117 in a direction away from thelight source 104.

The optical elements 119 of the light input region 117 are illustratedas lenticular grooves oriented orthogonally to major surfaces 106, 108.In other embodiments, the optical elements 119 have other suitableorientations and shapes, for example, lenticular grooves orientedparallel to major surfaces 106, 108, V-grooves oriented orthogonally tomajor surfaces 106, 108, V-grooves oriented parallel to major surfaces106, 108, lenses, or combinations thereof. Other exemplary opticalelements include light-scattering elements, which are typically featuresof indistinct shape or surface texture, such as printed features, inkjet printed features, selectively-deposited features, chemically etchedfeatures, laser etched features, and so forth. Other exemplary opticalelements include features of well-defined shape, such as V-grooves,lenticular grooves, and features of well-defined shape that are smallrelative to the linear dimensions of the light input edge 114, which aresometimes referred to as micro-optical elements for the light inputregion. The smaller of the length and width of a micro-optical elementis less than one-half of the longer of the length and width of the lightinput edge 114, and the larger of the length and width of themicro-optical element is less than the smaller of the length and widthof the light input edge 114. The length and width of the micro-opticalelement for the light input region is measured in the plane that isparallel to and includes the light input edge 114 of the light guide 102for flat light guides or along a surface contour for non-flat lightguides.

Micro-optical elements at the light input region are shaped topredictably refract light incident thereon. However, one or more of thesurfaces of the micro-optical elements may be modified, such asroughened, to produce a secondary effect on light incident thereon.Exemplary micro-optical elements are described in U.S. Pat. No.6,752,505 and, for the sake of brevity, will not be described in detailin this disclosure. The micro-optical elements for the light inputregion may vary in one or more of size, shape, depth or height, density,orientation, slope angle, or index of refraction such that a desiredoptical modifying characteristic is achieved over the correspondinglight input region.

In the illustrated embodiment, light input region 118 includes a planarsurface. As such, the light input region 118 provides little or nomodification of the light ray angle distribution of the light incidentthereon beyond that resulting from refraction at a plane surface. Thelight input region 118 is therefore considered specularly transmissive.In other embodiments, light input region 118 includes optical elementsthat are different than the optical elements 119 in light input region117 to provide a light ray angle distribution modification differentthan that provided by the light input region 117.

The lighting assembly 100 further includes a light source assembly 103(e.g., as shown in FIGS. 1 and 2). The light source assembly 103includes one or more light sources 104 positioned adjacent the lightinput edge 114. Each light source 104 is typically embodied as one ormore solid-state devices. In one embodiment, the light sources 104 aremounted to a printed circuit board (PCB) 105 (e.g., as shown in FIG. 1).Accordingly, the light sources 104 are fixed in position relative to oneanother. As described in greater detail below, the light sources 104 andthe light input edge 114 of the light guide 102 are variablypositionable relative to one another.

In some embodiments, the light sources 104 are positioned relative tothe light input regions 117, 118 such that the apportionment of thelight from each light source 104 between the light input regions 117,118 associated with the light source is the same for all the lightsources. Consequently, the light entering the light guide 102 has thesame characteristic (e.g., spectrum and/or light ray angle distribution)regardless of the light source from which it originated.

Exemplary light sources include such solid state devices as LEDs, laserdiodes, and organic LEDs (OLEDs). In an embodiment where the lightsource 104 includes one or more LEDs, the LEDs may be top-fire LEDs orside-fire LEDs, and may be broad spectrum LEDs (e.g., emits white light)or LEDs that emit light of a desired color or spectrum (e.g., red light,green light, blue light, or ultraviolet light). In one embodiment, thelight source 104 emits light with no operably-effective intensity atwavelengths greater than 500 nanometers (nm) (i.e., the light source 104emits light at wavelengths that are predominantly less than 500 nm). Insome embodiments, each light source 104 included in the lightingassembly 100 has the same nominal spectrum. In other embodiments, thelight sources are different from each other (e.g., two different typesof light sources alternatively located along the light source assemblyas will be described below with reference to FIGS. 20 and 21).

Although not specifically illustrated in detail, the light sourceassembly 103 also includes structural components (e.g., PCB 105 as shownin FIG. 1) to retain the light source 104. The light source assembly 103may additionally include: circuitry, power supply and/or electronics forcontrolling and driving the light source 104, and any other appropriatecomponents.

Each light source is associated with two or more light input regions ofthe light guide 102. In the example shown, two light input regions 117,118 are associated with the light source 104. Other examples have morethan two light input regions associated with each light source. Thelight source 104 and the associated light input regions are variablypositionable relative to one another such that light emitted by thelight source 104 is incident on the light input regions 117, 118 and isvariably apportioned between the light input regions depending on therelative positioning of the light input regions 117, 118 and the lightsource 104. In an example, the relative positioning of the light sourceand the light input region is varied by moving the light source along adirection parallel to the major surfaces 106, 108 and parallel to thelight input edge 114 of the light guide 102 (in a forward direction anda reverse direction) to selectively apportion light emitted from thelight source among the light input regions. In one embodiment, movingthe light source in the forward direction provides output light with afirst characteristic and moving the light source in the reversedirection provides output light with a second characteristic differentfrom the first characteristic.

For example, in FIG. 4, the light source 104 is located adjacent thelight input region 117 of the light input edge 114. Therefore, more ofthe light emitted from the light source 104 is incident on the lightinput region 117 than is incident on the light input region 118. Asfurther shown in FIGS. 5 and 6, the light source 104 has been movedlaterally by respective distances relative to the position shown in FIG.4 to vary the position of the light source 104 relative to the lightguide 102 and produce a corresponding change in the apportionment of thelight incident on the light input regions. For example, in FIG. 5 thelight source 104 is located adjacent the light input region 118 of thelight input edge 114. Therefore, more of the light emitted from thelight source 104 is incident on the light input region 118 than isincident on the light input region 117. In FIG. 6, the light source 104is located in an intermediate position adjacent both the light inputregion 117 and the light input region 118 of the light input edge 114.Therefore, similar amounts of the light emitted from the light source104 are incident on the light input region 117 and the light inputregion 118. By moving the light source 104 and the associated lightinput regions 117, 118 relative to one another, light emitted from thelight source is selectively apportioned between the light input regionsso that a characteristic of the light output from the lighting assemblyis modified based on the optical modifying characteristics of the lightinput regions 117, 118 and the relative positioning of the light source104 and the light input regions 117, 118.

In one embodiment, the relative positioning is varied manually by auser. In the example shown in FIG. 1, the lighting assembly 100 includesa user-manipulable mechanism 147 that moves one or both of the lightguide 102 and the light source 104 relative to the other to vary therelative positioning of the light input regions and the light source104. As shown in FIG. 1, the light source 104 is fixed relative to ahousing 140 and the light guide 102 is rotatably moveable relativethereto by the manual application of force to the mechanism 147. In theembodiment of FIG. 1, the mechanism 147 is a member that is secured tothe light guide 102 and slides over a portion of the housing 140 of thelight bulb 200. In one embodiment, the amount of movement may be limitedby stops (not shown). Other manually-operated mechanisms are possible.For instance, other types of sliders may be employed or a turnable knobmay act on the moveable component through a gear or drive train. Inother embodiments, the mechanism 147 is motorized to move one or both ofthe light guide 102 and the light source 104 relative to the other. Themotorized mechanism may be controlled by a control assembly (not shown)to adjust light output based on user input, feedback from sensors, or atriggering event. In still other embodiments, there is no mechanism 147and the adjustment is made by applying a positioning force, which in thecase of the exemplary cylinder is torque, directly to the moveable oneof the light source assembly 103 and the light guide 102.

Once positioned, the relative positioning of the light input regions andthe light source 104 remains unchanged until the user or controlassembly varies the relative positioning. Since constant motion of thelight guide 102 and the light source 104 relative to one another is notcontemplated during operation of the lighting assembly 100, the range ofmovement of the light guide 102 and/or the light source 104 may belimited. The range of movement may be limited to back-and-forth slidingthat moves the light input regions 117, 118 in and out of alignment withthe light source 104, rather than allowing infinite movement of thelight guide 102 or the light source 104 in one direction.

A visual indicator may be present to provide the user with an indicationof the modification of the light output of the lighting assembly 100. Inthe illustrated embodiment of FIG. 1, for example, markings 146 arepresent on the light guide 102 and align relative to a pointer 148 onthe housing to provide this indication.

FIGS. 7-10 illustrate part of another embodiment of a lighting assemblywith an adjustable light output. More specifically, FIGS. 7-10illustrate an exemplary application in which the light ray angledistribution of the light input to the light guide are modified suchthat that the light ray angle distribution of the light output from thelighting assembly depends on the relative positioning of the lightsource and the light input regions.

In the embodiment shown in FIGS. 7 and 8, the lighting assembly issimilar to that illustrated in FIGS. 3-6, but the light input regions117, 118 are located at a recessed portion of edge 114. The recessedposition of the light input regions 117, 118 does not change the effectof the optical modifying characteristics of the light input regions 117,118 on the light incident thereon, but the recessed configuration issimply shown to illustrate that the light guide 102 may be any suitableshape. Light input region 117 includes optical elements 119 illustratedas lenticular grooves oriented parallel to the major surfaces 106, 108.Light input region 118 includes a planar surface.

FIGS. 7 and 9 illustrate a relative positioning of the light source 104and the light input edge 114 wherein more of the light emitted from thelight source is incident on light input region 117 than on light inputregion 118. Referring first to FIG. 7, light input region 117 includeslenticular grooves oriented parallel to the major surfaces 106, 108. Thelenticular grooves change the light ray angle distribution of the lightemitted from the light source 104 and incident on the first light inputregion 117. The lenticular grooves spread the light entering the lightguide 102 through the light input region 117 in a plane orthogonal tothe major surfaces 106, 108 and the light input edge 114. Referring nowto FIG. 9, more of the light entering the light guide 102 is incident onthe major surfaces 106, 108 at smaller angles of incidence (relative tothe normal) due to refraction of the light at the optical elements 119and therefore more of the light propagates in higher modes in the lightguide 102. As described above, the first and second major surfaces 106,108 include light extracting elements (not shown). As a result of thegreater amount of light propagating in the higher propagation modes,more of the light emitted from the light source and incident on thefirst light input region 117 exits through one or both of the firstmajor surface 106 and the second major surface 108 than through the edge116, as illustrated in FIG. 9.

FIGS. 8 and 10 illustrate a relative positioning of the light source 104and the light input edge 114 wherein more of the light emitted from thelight source is incident on the light input region 118 than is incidenton the light input region 117. Referring first to FIG. 8, the lightinput region 118 has a planar surface. The planar surface of the lightinput region 118 is specularly transmissive. Referring now to FIG. 10,more of the light entering the light guide 102 through the light inputregion 118 is incident on the major surfaces at larger angles ofincidence (relative to the normal) and therefore more of the lightpropagates in the light guide at lower modes in the light guide. As aresult of the greater amount of light propagating in the lowerpropagation modes, more of the light emitted from the light source 104and incident on the second light input region 118 exits the light guide102 through the edge 116 than through the major surfaces 106, 108.

The above-described embodiments exemplify modification of the light rayangle distribution of the light input to the light guide 102 and, hence,the light ray angle distribution of the output light. The followingembodiments provide examples of modification of the spectrum of thelight incident on the light input regions. FIGS. 11-13 illustrate anexample of a light input edge 114 having three light input regions 217,218, 219, wherein at least one of the input regions includes a spectrumadjuster. Accordingly, FIGS. 11-13 illustrate an embodiment where thevariable positioning of light source 104 and the associated light inputregions relative to one another determines a modification of thespectrum of the light input to the light guide 102.

In the illustrated embodiment, the light input region 217 includes aspectrum adjuster, and the light input region 219 includes a spectrumadjuster that is different than the spectrum adjuster of the light inputregion 217. The presence of the respective spectrum adjusters in thelight input regions 217, 219 is denoted by hatching. Light input region218 is specularly transmissive and does not adjust spectrum. However,embodiments are contemplated where the light input region 218 alsoincludes a spectrum adjuster.

In one embodiment, the respective spectrum adjuster in the light inputregions is a region of wavelength shifting material. Wavelength shiftingis used herein to refer to a process in which a material absorbs lightof certain wavelengths, and reemits light at one or more differentwavelengths. The wavelength-shifting material includes one or more of aphosphor material, a luminescent material, a luminescent nanomaterialsuch as a quantum dot material, a conjugated polymer material, anorganic fluorescent dye, an organic phosphorescent dye, andlanthanide-doped garnet. In another embodiment, the respective spectrumadjuster in the light input regions is a region of color attenuatingmaterial, for example, a color filter. In other embodiments, the lightinput regions respectively include both a wavelength shifting materialand a color attenuating material. For example, the spectrum adjuster ofone of the light input regions may include a wavelength shiftingmaterial and the spectrum adjuster of another of the light input regionsmay include a color attenuating material.

Similar to the above-described embodiments, the light source 104 and thelight input regions 217, 218, 219 are variably positionable relative toone another such that light emitted from the light source and incidenton the light input regions is apportioned among the light input regionsdepending on the relative positioning of the light input regions 217,218, 219 and the light source 104. Accordingly, the light source 104 maybe located adjacent the light input edge in a position corresponding toany one of the light input regions 217, 218, 219. For example, in FIG.11, the light source 104 is located adjacent the light input region 217of the light input edge 114 such that more of the light emitted from thelight source 104 is incident on the light input region 217 than on thelight input regions 218, 219. In FIG. 12, the light source 104 islocated adjacent the light input region 218 of the light input edge 114such that more of the light emitted from the light source 104 isincident on the light input region 218 than on the light input regions217, 219. Similarly, when the light source 104 is located adjacent thelight input region 219 of the light input edge 114, more of the lightemitted from the light source 104 is incident on the light input region219 than on the light input regions 217, 218. Light emitted from thelight source 104 and incident on the input region 217 is input to thelight guide with a first spectrum, light emitted from the light sourceand incident on the light input region 218 is input to the light guidewith a second spectrum, and light emitted from the light source andincident on the light input region 219 is input to the light guide witha third spectrum, in accordance with the light modifying characteristicsof the respective light input regions.

The light source 104 may also be located adjacent a region of the lightinput edge 114 in an intermediate position between two adjacent ones ofthe light input regions 217, 218, 219. For example, in FIG. 13, thelight source 104 is located in an intermediate position adjacent boththe light input region 218 and the light input region 219 of the lightinput edge 114 such that a portion of the light emitted from the lightsource 104 is incident on the light input region 218 and another portion(typically the remainder) of the light emitted from the light source isincident on the light input region 219. Accordingly, the light input tothe light guide with different spectra from the respective light inputregions mixes in the light guide to provide light with a spectrum thatis the sum of the spectra of light input to the light guide 102 throughthe light input regions 218, 219 weighted in accordance with theapportioning of the light between the light input regions 218, 219.

FIGS. 14-16 illustrate an exemplary application of the lighting assembly100 as described with reference to FIGS. 11-13. More specifically, FIGS.14-16 illustrate an application in which the spectrum of the lightoutput from the lighting assembly is modified based on relativepositioning of the light source 104 and the light input regions 217,218, 219. The application will be described with reference to an examplein which the color temperature of the output light from the lightingassembly 100 is varied.

Many LED light sources 104 emit light in a range of wavelengths intendedto achieve a corresponding color temperature. However, within batches ofLEDs having the same nominal color temperature, there is variation ofcolor temperature from LED to LED. Also, sometimes broad-spectrum LEDs(e.g., “white light” LEDs) or groups of tri-color LEDs (e.g., a red LED,a blue LED and a green LED whose outputs combine to produce white light)do not produce a color temperature that is desirable to a user orappropriate for a certain lighting application. To modify the colortemperature of the light output from the lighting assembly 100, thelight input region 217 and the light input region 219 may be used tomodify the spectrum (color temperature in this case) of the light outputby the lighting assembly 100. In this example, the light input region217 modifies the light output to be warmer (either or both of more redand less blue) and the light input region 219 modifies the light outputto be cooler (either or both of more blue and less red). The light inputregion 218 is specularly transmissive, and light incident thereon entersthe light guide with the same spectrum (color temperature in this case)as the light emitted from the light source 104. The relative positioningof the light source 104 and the light input regions 217, 218, 219 (asillustrated in FIGS. 14-16) varies the apportionment of the incidentlight between the light input regions, therefore resulting in acorresponding variation in color temperature of the light output fromthe lighting assembly 100.

Some embodiments are configured to allow a user to vary the colortemperature of light output from the lighting assembly 100 in order toachieve a desired color temperature. Other embodiments are configured toallow a manufacturer of the lighting assembly 100 to vary the colortemperature of light output from the lighting assembly 100 to compensatefor different color temperatures associated with different lots of lightsources 104. This allows the lighting assembly manufacturer to source abroader range of light sources 104 from one or more suppliers and stillmanufacture lighting assemblies with a defined, consistent colortemperature.

In some embodiments, the relative positioning of the light input regions217, 218, 219 and the light source 104 is varied by the manufacturer ofthe lighting assembly 100 until the output light has a definedcharacteristic. The relative positioning is then fixed by themanufacturer, and the lighting assembly 100 is configured in a manner tominimize the ability of a user of the lighting assembly 100 to furthervary the relative positioning. In other embodiments, the user has theability to vary the relative positioning.

Embodiments are also contemplated where one or more of the respectivelight input regions associated with a light source modifies both thespectrum and the light ray angle distribution of the light incidentthereon. FIG. 17 illustrates an exemplary configuration of light inputregions 217, 218, 219 and 317, 318, 319 of light input edge 114, whereinat least one of the input regions includes a spectrum adjuster andoptical elements. Similar to the light input regions described abovewith reference to FIGS. 11-13, light input regions 217, 219 each includespectrum adjusters, and light input region 218 is specularlytransmissive. Light input region 317 includes a spectrum adjustersimilar to the spectrum adjuster of light input region 217, and lightinput region 319 includes a spectrum adjuster similar to the spectrumadjuster of light input region 219. In addition, light input regions317, 318, 319 include optical elements 220 that modify the light rayangle distribution of the light incident thereon. In the illustratedembodiment, the optical elements 220 of light input regions 317, 318,319 are similar.

The relative positioning of the light source 104 and the light inputregions 217, 218, 219 modifies the spectrum of the light input to thelight guide 102 with a first light ray angle distribution, and therelative positioning of the light source 104 and the light input regions317, 318, 319 modifies the spectrum of the light input to the lightguide 102 with a second light ray angle distribution, different from thefirst light ray angle distribution.

In the above-described examples, the boundaries between the adjacentlight input regions are depicted as extending orthogonally to the planeof the major surfaces 106, 108. In other examples (not shown), theboundaries of the light input regions extend non-orthogonally to theplane of the major surfaces 106, 108. In one particular example, theboundaries slope towards one another, allowing the light from the lightsource 104 to be apportioned among three light input regions dependingon the relative positioning of the light source 104 and the light inputregions along a direction parallel to the major surfaces 106, 108 of thelight guide 102.

The embodiments described thus far have illustrated relative positioningof the light source 104 and light input regions along one direction(i.e., along a direction parallel to the major surfaces 106, 108 of thelight guide 102 and the light input edge 114 (e.g., FIGS. 4-6)). Asillustrated in FIGS. 18 and 19, the light source 104 and light inputregions are variably positionable relative to one another along twodirections (i.e., along a direction parallel to the major surfaces 106,108 of the light guide 102, and along a direction orthogonal to themajor surfaces 106, 108 of the light guide 102). Accordingly, twovariables are provided for modifying the characteristics of the lightoutput of the lighting assembly 100. In the examples shown in FIGS. 18and 19, light input regions are arrayed along both the first direction131 and second direction 132 relative to light input edge 114 of thelight guide. The light source 104 and light input regions are relativelypositionable along two directions 131, 132 to apportion the lightemitted from the light source between two, three or four of the lightinput regions.

FIG. 18 illustrates an embodiment having three light input regions 417,418, 419. FIG. 19 illustrates an embodiment having four light inputregions 417, 418, 419, 420. Consistent with the above-describedembodiments, one or more of the respective light input regions includesoptical elements and/or a spectrum adjuster.

In one embodiment, the relative positioning of the light source 104 andthe light input regions along the first direction 131 provides a firstmodification of the spectrum, and the relative positioning of the lightsource and the light input regions along the second direction 132, inthe example shown, orthogonal to the first direction, provides a secondmodification of the spectrum, different from the first modification ofthe spectrum. In an example of the embodiment shown in FIG. 18, thelight input regions 417, 418 include respective spectrum adjusters andthe light input region 419 is specularly transmissive and does notadjust spectrum. The relative positioning of the light source 104 alongthe two directions 131, 132 apportions the light from the light sourceamong the light input regions 417, 418, 419 to provide a desired lightoutput spectrum from the lighting assembly 100.

In another embodiment, moving the light source along the first direction131 modifies the light ray angle distribution and moving the lightsource along the second direction 132 modifies the spectrum. In anexample of the embodiment shown in FIG. 19, light input regions 417, 418include similar spectrum adjusters, and light input regions 418, 420include similar optical elements. Light input region 419 is specularlytransmissive and does not adjust spectrum. By moving the light sourcealong the first direction 131, output light with a desired light rayangle distribution is obtained. By moving the light source along thesecond direction 132, output light with a desired light output spectrumis obtained. By moving the light source along the first direction 131and the second direction 132, output light with a desired combination oflight ray angle distribution and spectrum is obtained.

FIGS. 20 and 21 illustrate another embodiment in which the lightingassembly includes multiple types of light sources 204, 304. In thisembodiment, the two types of light sources are alternately located alongthe light input edge 114 of the light guide 102. Light sources of afirst light source type 204 emit light with a first spectrum, and lightsources of a second light source type 304 emit light with a secondspectrum, different from the first spectrum. For example, in oneembodiment, the light sources of the first light source type 204 emit“white” light and the light sources of the second light source type 304emit red light. The light sources 204, 304 are mounted on a common PCB(not shown) such that the light sources and the associated light inputregions of the light guide 102 are positionable relative to one anotherin concert. Light emitted from each light source 204, 304 is incident onone or more light input regions.

Two types of light input regions 517, 518 are alternately located alongthe input edge 114 of the light guide 102. The light input regions of afirst light input region type 517 have a first transmissivity and thelight input regions of a second light input region type 518 have asecond transmissivity, different from the first transmissivity. In oneembodiment, light input region types 517, 518 include at least one of areflective material and a light absorbing material to reduce theintensity of light input into the light guide 102.

In the illustrated example, the lighting assembly 100 is configured suchthat, for a given positional relationship between the light sources 204,304 and the light input regions 517, 518, the apportionment of the lightfrom each type of light source between the light input regions is thesame. For example, FIG. 20 illustrates a relative positioning whereinmore of the light emitted from the light sources 204 of the first lightsource type is incident on the light input regions 517 of the firstlight input region type than on the light input regions 518 of thesecond light input region type; and more of the light emitted from thelight sources 304 of the second light source type is incident on thelight input regions 518 of the second light input region type than onthe light input regions 517 of the first light input region type.

FIG. 21 illustrates a relative positioning of the light sources and thelight input regions wherein a portion of the light emitted from thelight sources 204 of the first light source type and a portion of thelight emitted from the light sources 304 of the second light source typeare incident on a same one of the light input regions 517, 518 of thefirst and second light input region types. Light input to the lightguide 102 from the light sources 204 of the first light source type andlight input to the light guide 102 from the light sources 304 of thesecond light source type mix in the light guide to provide light with aspectrum that is the sum of the spectra of light input to the lightguide 102 from the light sources 204, 304 of the first and second lightsource types weighted in accordance with the apportioning of the lightbetween the light input regions of the first and second light inputregion types. In the illustrated example, the transmissivity of therespective light input regions 517, 518 of the first and second lightinput region types and the relative positioning of the light sources204, 304 of the first and second light source types collectively controla characteristic (in this example, spectrum) of the light output fromthe lighting assembly 100.

Other applications are apparent based on using any of the above-notedlight modifying characteristics for the light input regions.

Returning to FIG. 1, additional details regarding the lighting assembly100 when embodied as the light bulb 200 will be described. The lightbulb 200 includes a base 150. The illustrated base 150 is an Edisonbase, but other types of bases 150 may be used, including anycommercially-standard base or proprietary base used for mechanicallysecuring an incandescent bulb, a fluorescent bulb, a compact fluorescentbulb (CFL), a halogen bulb, a high intensity discharge (HID) bulb, anarc lamp, or any other type of bulb into a lamp, a lighting fixture, aflashlight, a socket, etc., and/or for supplying electricity thereto.The light bulb 200 typically further includes a heat sink 151 thatdissipates heat generated by the light sources 104. The heat sink 151 ofthe illustrated embodiment forms part of the housing 140. Parts of thelight bulb 200, such as the light guide 102 and the light source 104,are described above with reference to FIGS. 3-21.

References herein to a “light bulb” are meant to broadly encompasslight-producing devices that fit into and engage any of various fixturesfor mechanically mounting the light-producing device and for providingelectrical power thereto. Examples of such fixtures include, withoutlimitation, screw-in fixtures for engaging an Edison light bulb base, abayonet fixture for engaging a bayonet light bulb base, or a bi-pinfixture for engaging a bi-pin light bulb base. Thus the term “lightbulb,” by itself, does not provide any limitation on the shape of thelight-producing device, or the mechanism by which light is produced fromelectric power. Also, the light bulb need not have an enclosed envelopeforming an environment for light generation. The light bulb may conformto American National Standards Institute (ANSI) or other standards forelectric lamps, but the light bulb does not necessarily have to havethis conformance.

Returning to FIG. 2, additional details regarding the lighting fixture300 will be described. The lighting fixture 300 may be a hanging light(as shown), a ceiling light (e.g., an assembly to fit in a drop-downceiling or secure flush to a ceiling), a wall sconce, a table lamp, atask light, or any other illumination device. The lighting fixture 300includes a housing 140 for retaining the light source assembly 103 andthe light guide 102. The housing 140 may retain or may serve as a heatsink. In some embodiments, the lighting fixture 300 includes a mechanism160 (e.g., a chain or wire in the case of a hanging light, clips orfasteners in the case of a ceiling light or wall sconce, etc.) tomechanically secure the lighting assembly to a retaining structure(e.g., a ceiling, a wall, etc.). In other embodiments, the mechanism 160is a stand and/or base assembly to allow the lighting fixture 300 tofunction as a floor lamp, table lamp, task lamp, etc. Electrical poweris supplied to the lighting fixture through appropriate conductors,which in some cases may form part of or pass through the mechanism 160.Parts of the lighting fixture, such as the light guide 102 and the lightsource 104, are described above with reference to FIGS. 3-21.

In this disclosure, the phrase “one of” followed by a list is intendedto mean the elements of the list in the alterative. For example, “one ofA, B and C” means A or B or C. The phrase “at least one of” followed bya list is intended to mean one or more of the elements of the list inthe alterative. For example, “at least one of A, B and C” means A or Bor C or (A and B) or (A and C) or (B and C) or (A and B and C).

What is claimed is:
 1. A lighting assembly, comprising: a light guide topropagate light by total internal reflection, the light guide comprisingopposed major surfaces and a light input edge extending between theopposed major surfaces, the light input edge comprising light inputregions, at least one of the light input regions associated with anoptical modifying characteristic; a light source assembly comprising alight source, the light source located adjacent the light input regions;and a housing retaining the light source assembly and the light guide,and as retained by the housing, the light source and the light inputregions are variably positionable relative to one another to vary alocation at which light is incident on the light input regions such thatlight emitted from the light source is selectively apportioned betweenthe light input regions so that a characteristic of the light outputfrom the lighting assembly is modified based on the optical modifyingcharacteristic of the at least one of the light input regions and therelative positioning of the light source and the light input regions. 2.The lighting assembly of claim 1, wherein the characteristic of thelight output from the lighting assembly that is modified is spectrum. 3.The lighting assembly of claim 1, wherein the characteristic of thelight output from the lighting assembly that is modified is light rayangle distribution.
 4. The lighting assembly of claim 1, wherein thelight source and the light input regions are variably positionablerelative to one another between a first position wherein more of thelight emitted from the light source is incident on one of the lightinput regions than on another of the light input regions, and a secondposition wherein a portion of the light emitted from the light source isincident on the one of the light input regions and a portion of thelight emitted from the light source is incident on the other of thelight input regions, the portions depending on the relative positioningof the light source and the light input regions.
 5. The lightingassembly of claim 1, wherein one of the light input regions comprises anoptical element.
 6. The lighting assembly of claim 5, wherein theoptical element comprises one or more of: lenticular grooves, V-grooves,micro-optical elements, and light-scattering elements.
 7. The lightingassembly of claim 5, wherein another of the light input regions isplanar.
 8. The lighting assembly of claim 7, wherein: the light guidefurther comprises an end edge distal the light input regions and lightextracting elements at at least one of the opposed major surfaces; theone of the light input regions is configured to direct light input tothe light guide such that more of the light emitted from the lightsource, incident on the one of the light input regions, and input to thelight guide is incident the opposed major surfaces and extracted by thelight extracting elements through at least one of the opposed majorsurfaces than is incident and exits through the end edge; and theanother of the light input regions is configured to direct light inputto the light guide such that more of the light emitted from the lightsource, incident on the one of the light input regions, and input to thelight guide is incident and exits through the end edge than is incidentthe opposed major surfaces and extracted by the light extractingelements through at least one of the opposed major surfaces.
 9. Thelighting assembly of claim 5, wherein the light input regions compriseoptical elements configured to provide the light input regions withdifferent optical modifying characteristics.
 10. The lighting assemblyof claim 9, wherein: the light guide further comprises an end edgedistal the light input regions and light extracting elements at at leastone of the opposed major surfaces; the one of the light input regions isconfigured to direct light input to the light guide such that more ofthe light emitted from the light source, incident on the one of thelight input regions, and input to the light guide is incident theopposed major surfaces and extracted by the light extracting elementsthrough at least one of the opposed major surfaces than is incident andexits through the end edge; and another of the light input regions isconfigured to direct light input to the light guide such that more ofthe light emitted from the light source, incident on the one of thelight input regions, and input to the light guide is incident and exitsthrough the end edge than is incident the opposed major surfaces andextracted by the light extracting elements through at least one of theopposed major surfaces.
 11. The lighting assembly of claim 1, whereinone of the light input regions comprises a spectrum adjuster.
 12. Thelighting assembly of claim 11, wherein the spectrum adjuster comprises acolor attenuating material.
 13. The lighting assembly of claim 11,wherein the spectrum adjuster comprises a wavelength-shifting material.14. The lighting assembly of claim 11, wherein another of the lightinput regions is specularly transmissive.
 15. The lighting assembly ofclaim 11, wherein: the light emitted from the light source and incidenton the spectrum adjuster in one of the light input regions is input tothe light guide with a first spectrum; the light emitted from the lightsource and incident on another of the light input regions is input tothe light guide with a second spectrum, different from the firstspectrum; and light input to the light guide with the first spectrum andlight input to the light guide with the second spectrum mix in the lightguide to form light having a combined spectrum that is the sum of thefirst spectrum and the second spectrum weighted in accordance with theapportioning of the light between the one of the light input regions andthe other of the light input regions.
 16. The lighting assembly of claim11, wherein one of the light input regions comprises an optical element.17. The lighting assembly of claim 16, wherein the optical elementcomprises one or more of: lenticular grooves, V-grooves, micro-opticalelements, and light-scattering elements.
 18. The lighting assembly ofclaim 11, wherein the light source and the light input regions arevariably positionable relative to one another along in a first directionand a second direction to selectively apportion light emitted from thelight source among at least three of the light input regions.
 19. Thelighting assembly of claim 18, wherein varying the relative positioningof the light source and the light input regions along the firstdirection modifies the spectrum of the output light in accordance with afirst optical modifying characteristic and varying the relativepositioning of the light source and the light input regions along thesecond direction modifies the spectrum of the output light in accordancewith a second optical modifying characteristic different from the firstoptical modifying characteristic.
 20. The lighting assembly of claim 18,wherein varying the relative positioning of the light source and thelight input regions along the first direction modifies the spectrum ofthe output light and varying the relative positioning of the lightsource and the light input regions along the second direction modifiesthe light ray angle distribution of the output light.
 21. The lightingassembly of claim 11, wherein: another of the light input regionscomprises a spectrum adjuster; the respective spectrum adjusters eachmodify the spectrum of light incident thereon such that: the lightemitted from the light source and incident on the spectrum adjuster inthe one of the light input regions is input to the light guide with afirst spectrum; and the light emitted from the light source and incidenton the spectrum adjuster in the other of the light input regions isinput to the light guide with a second spectrum, different from thefirst spectrum; the light emitted from the light source and incident ona third of the light input regions is input to the light guide with athird spectrum different from the first spectrum and the secondspectrum; and light input to the light guide with the first spectrum,light input to the light with the second spectrum, and light input tothe light guide with the third spectrum mix in the light guide to formlight having a combined spectrum that is the sum of the first spectrum,the second spectrum, and the third spectrum weighted in accordance withthe apportioning of the light between the one of the light inputregions, the other of the light input regions, and the third of thelight input regions.
 22. The lighting assembly of claim 1, wherein thelight source and the light input regions are variably positionablerelative to one another such that a portion of the light emitted fromthe light source is incident on one of the light input regions, aportion of the light emitted from the light source is incident onanother of the light input regions, and a portion of the light emittedfrom the light source is incident on a third of the light input regions.23. The lighting assembly of claim 1, wherein the light source comprisesa solid state light source.
 24. The lighting assembly of claim 23,wherein the light source emits light with no operably-effectiveintensity at wavelengths greater than 500 nm.
 25. The lighting assemblyof claim 1, wherein one of the light input regions has a firsttransmissivity and another of the light input regions has a secondtransmissivity, different from the first transmissivity.
 26. Thelighting assembly of claim 25, wherein one of the light input regionscomprises at least one of a reflective material and a light absorbingmaterial.
 27. The lighting assembly of claim 26, further comprising anadditional light source located adjacent the light input regions, thelight sources and the light input regions variably positionable relativeto one another to input light at different locations relative to thelight input regions.
 28. The lighting assembly of claim 27, wherein thelight sources and the light input regions are variably positionablerelative to one another to a position wherein more of the light emittedfrom the light source is incident on one of the light input regions thanon another of the light input regions, and more of the light emittedfrom the additional light source is incident on the other of the lightinput regions than on the one of the light input regions.
 29. Thelighting assembly of claim 27, wherein the light sources and the lightinput regions are variably positionable relative to one another to aposition wherein a portion of the light emitted from the light sourceand a portion of the light emitted from the additional light source areincident on a same one of the light input regions.
 30. The lightingassembly of claim 27, wherein: the light source emits light with a firstspectrum; and the additional light source emits light with a spectrumdifferent from the first spectrum.
 31. The lighting assembly of claim30, wherein light input to the light guide with the first spectrum andlight input to the light guide with the second spectrum mix in the lightguide to form light having a combined spectrum that is the sum of thefirst spectrum and the second spectrum weighted in accordance with theapportioning of the light with the first spectrum and the light with thesecond spectrum between the one of the light input regions and the otherof the light input regions.
 32. A lighting assembly, comprising: a lightguide to propagate light by total internal reflection, the light guidecomprising opposed major surfaces and a light input edge extendingbetween the opposed major surfaces, the light input edge comprisinglight input regions, at least one of the light input regions associatedwith an optical modifying characteristic; a light source assemblycomprising a light source, the light source located adjacent the lightinput regions, the light source and the light input regions variablypositionable relative to one another to vary a location at which lightis incident on the light input regions such that light emitted from thelight source is selectively apportioned between the light input regionsso that a characteristic of the light output from the lighting assemblyis modified based on the optical modifying characteristic of the atleast one of the light input regions and the relative positioning of thelight source and the light input regions; and a user-manipulableadjustment mechanism coupled to one or both of the light guide and thelight source and configured to adjust the positioning of the lightsource relative to the light input regions.